Chitosan coated cotton cloth supported zero-valent nanoparticles: Simple but economically viable, efficient and easily retrievable catalysts

Effective hydrogen production and coupling degradation of organics (4-nitrophenol, methylene blue, and Rhodamine B) in wastewater by electrospun PAN@Fe0 composite nanofibers

The pursuit of clean energy generation and environmental preservation is of utmost importance for societal progress. However, couple clean energy production and pollution control is still a difficulty. In this study, a novel electrospun composite mat, with nano zero valent iron (Fe0, nZVI) encapsulated into polyacrylonitrile (PAN) nanofibers was acted as a catalyst. The activation energy (Ea) for the hydrolysis of NaBH4 to produce hydrogen is 22 kJ·mol-1, hydrogen atom utilization efficiency (HGE) of NaBH4 is 60.80%. Three kinds of organic dyes 4-nitrophenol (4-NP), methylene blue (MB), and Rhodamine B (RhB) were served as the model pollutant, to construct NaBH4-organic system for energy production and pollution reduction. The NaBH4-organic system demonstrates a collaborative capability to simultaneously remove organic pollutants and generate hydrogen, with a coupling equilibrium point between the two processes. The hydrogen generation rate (HGR) and HGE increased with the concentration of pollutants increased. The degradation of 4-NP, MB, and RhB followed pseudo-first-order kinetics, with RhB degrading dosage 20 and 44 times higher than 4-NP and MB, respectively. H2 and H· contributed to the organic degradation. nZVI directly participated in the formation H2 and H·. PAN@Fe0 possessed good recyclability and moderate cost. The degradation process adhered to the classical surface reaction controlled Langmuir-Hinshelwood (L-H) model. The integration of synergistic production capacity and pollutant degradation aligns well with the principles of green chemistry and sustainable development. This study demonstrates a novel approach to no precursor loss catalysts preparation, efficient production clean H2, advanced treatment of dye-containing wastewater, carbon neutral operation of sewage treatment plant.

Antibacterial composite films of oxidized alginate-chitosan-ZnO anchored Cu nanoparticles for the degradation of organic pollutants

The growing population and urbanization have adversely affected the environment including water. The waste water from industries has affected not only human but also animals. The availability of clean water is one of the foremost needs for living organism. This makes very urgent to find reliable solutions for cleaning waste water. These days catalysis is one the best solutions to remove and degrade organic pollutants. In this work, porous composite polymer films have been designed through facile method which were employed to stabilize zero-valent metal nanoparticles (NPs). The sustainable, environmentally friendly polymer matrix with attached metal NPs was applied for the effective catalytic degradation of both phenolic compounds and organic dyes. The different composite films consist of ZnO NPs embedded in an Oxidized Alginate-Chitosan (OAlg-CS) biomatrix named as OAlg-CS/ZnO with various percentages of ZnO as a support for metallic Cu NPs. The ZnO NPs have been incorporated into OAlg-CS polymer with 10, 15, and 20 wt% and are designated as OAlg-CS/ZnO-10, OAlg-CS/ZnO-15, OAlg-CS/ZnO-20. Various analytical techniques were utilized to investigate the shape, morphology, elemental composition, functional groups and stability of the composite films. All these polymer nanocomposite films were then evaluated for removal of model organic pollutants comprising p-nitrophenol (4-NP), methylene blue (MB), and methyl orange (MO). The Kapp value for 4-NP was 2.19 × 10-1 min-1, 4.68 × 10-1 min-1 for MO and 8.99× 10-1 min-1 for MB. The experimental results demonstrated that OAlg-CS/ZnO-20 films show the highest catalytic activity as compared to OAlg-CS/ZnO, OAlg-CS/ZnO-10, and OAlg-CS/ZnO-15. The order of rate constants for nitrophenol and dyes using OAlg-CS/ZnO-20 was found to be MB ˃ MO ˃ 4-NP, showing the selectivity of these composite films. The prepared composite films were also investigated for their antibacterial activity against Gram-positive and Gram-negative bacteria and all the films exhibited good anti-bacterial activity, with OAlg-CS/ZnO-20 showed the highest anti-bacterial activity.

Biological scaffold as potential platforms for stem cells: Current development and applications in wound healing

Wound repair is a complex challenge for both clinical practitioners and researchers. Conventional approaches for wound repair have several limitations. Stem cell-based therapy has emerged as a novel strategy to address this issue, exhibiting significant potential for enhancing wound healing rates, improving wound quality, and promoting skin regeneration. However, the use of stem cells in skin regeneration presents several challenges. Recently, stem cells and biomaterials have been identified as crucial components of the wound-healing process. Combination therapy involving the development of biocompatible scaffolds, accompanying cells, multiple biological factors, and structures resembling the natural extracellular matrix (ECM) has gained considerable attention. Biological scaffolds encompass a range of biomaterials that serve as platforms for seeding stem cells, providing them with an environment conducive to growth, similar to that of the ECM. These scaffolds facilitate the delivery and application of stem cells for tissue regeneration and wound healing. This article provides a comprehensive review of the current developments and applications of biological scaffolds for stem cells in wound healing, emphasizing their capacity to facilitate stem cell adhesion, proliferation, differentiation, and paracrine functions. Additionally, we identify the pivotal characteristics of the scaffolds that contribute to enhanced cellular activity.

An efficient wastewater treatment through reduction of organic dyes using Ag nanoparticles supported on cellulose gum beads

This work reports silver nanoparticles (AgNPs) supported on biopolymer carboxymethyl cellulose beads (Ag-CMC) serves as an efficient catalyst in the reduction process of p-nitrophenol (p-NP) and methyl orange (MO). For Ag-CMC synthesis, first CMC beads were prepared by crosslinking the CMC solution in aluminium nitrate solution and then the CMC beads were introduced into AgNO3 solution to adsorb Ag ions. Field emission scanning electron microscopy (FE-SEM) analysis suggests the uniform distribution of Ag nanoparticles on the CMC beads. The X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analysis revealed the metallic and fcc planes of AgNPs, respectively, in the Ag-CMC catalyst. The Ag-CMC catalyst exhibits remarkable reduction activity for the p-NP and MO dyes with the highest rate constant (kapp) of a chemical reaction is 0.519 and 0.697 min-1, respectively. Comparative reduction studies of Ag-CMC with CMC, Fe-CMC and Co-CMC disclosed that Ag-CMC containing AgNPs is an important factore in reducing the organic pollutants like p-NP and MO dyes. During the recyclability tests, the Ag-CMC also maintained high reduction activity, which suggests that CMC protects the AgNPs from leaching during dye reduction reactions.

Efficient Reduction in Methylene Blue Using Palladium Nanoparticles Supported by Melamine-Based Polymer

In this work, palladium nanoparticles, supported by polyaminals (Pd@PAN-NA), were synthesized via a reverse double solvent approach and used as a nano catalyst. The thermogravimetric and the elemental analysis revealed that the catalyst had good dispersity and improved thermal stability. The catalytic activity of the prepared Pd@PAN-NA catalyst was studied for a methylene blue chemical reaction in the presence of NaBH4 as a reducing agent. The effect of the catalyst dose, pH, and dye initial concentration were examined to optimize the chemical reduction conditions. The prepared catalyst Pd@PAN-NA removed 99.8% of methylene blue organic dye, indicating its potential effect for treating waste and contaminated water.

Developing Enzyme Immobilization with Fibrous Membranes: Longevity and Characterization Considerations

Fibrous membranes offer broad opportunities to deploy immobilized enzymes in new reactor and application designs, including multiphase continuous flow-through reactions. Enzyme immobilization is a technology strategy that simplifies the separation of otherwise soluble catalytic proteins from liquid reaction media and imparts stabilization and performance enhancement. Flexible immobilization matrices made from fibers have versatile physical attributes, such as high surface area, light weight, and controllable porosity, which give them membrane-like characteristics, while simultaneously providing good mechanical properties for creating functional filters, sensors, scaffolds, and other interface-active biocatalytic materials. This review examines immobilization strategies for enzymes on fibrous membrane-like polymeric supports involving all three fundamental mechanisms of post-immobilization, incorporation, and coating. Post-immobilization offers an infinite selection of matrix materials, but may encounter loading and durability issues, while incorporation offers longevity but has more limited material options and may present mass transfer obstacles. Coating techniques on fibrous materials at different geometric scales are a growing trend in making membranes that integrate biocatalytic functionality with versatile physical supports. Biocatalytic performance parameters and characterization techniques for immobilized enzymes are described, including several emerging techniques of special relevance for fibrous immobilized enzymes. Diverse application examples from the literature, focusing on fibrous matrices, are summarized, and biocatalyst longevity is emphasized as a critical performance parameter that needs increased attention to advance concepts from lab scale to broader utilization. This consolidation of fabrication, performance measurement, and characterization techniques, with guiding examples highlighted, is intended to inspire future innovations in enzyme immobilization with fibrous membranes and expand their uses in novel reactors and processes.

Green preparation of silver nanocluster composite AgNCs@CF-g-PAA and its application: 4-NP catalytic reduction and hydrogen production

4-Nitrophenol (4-NP) is a serious organic environmental pollutant. Conversion of 4-nitrophenol to 4-aminophenol (4-AP) by catalytic hydrogenation is an effective solution. In this work, a catalyst (AgNCs@CF-g-PAA) loaded with silver nanoclusters (AgNCs) was prepared by radiation technique. Firstly, the template polyacrylic acid (PAA) was grafted onto the cotton fiber (CF) by radiation grafting technique to obtain a solid template (CF-g-PAA). After that, AgNCs were synthesized in situ on CF-g-PAA by radiation reduction, and the composite material AgNCs@CF-g-PAA was obtained directly. AgNCs@CF-g-PAA has an obvious photoluminescence phenomenon, which is attributed to the stable AgNCs binding to the carboxyl on the PAA molecular chain. Due to the extremely small size of AgNCs, AgNCs@CF-g-PAA has good catalytic characteristics. The prepared AgNCs@CF-g-PAA catalyst has a very high catalytic rate for the hydrogenation of 4-NP. Even at high concentrations of 4-NP, AgNCs@CF-g-PAA can still maintain a high catalytic rate. At the same time, the AgNCs@CF-g-PAA catalyst can also be used to catalyze the rapid hydrolysis of sodium borohydride, which is conducive to hydrogen production. In summary, we have prepared a practical catalyst AgNCs@CF-g-PAA with high catalytic performance based on cheap raw materials and a simple synthesis route, which provides a catalyst candidate for the treatment of water contaminant 4-NP and the production of hydrogen from sodium borohydride.

Fabrication of 3D Gelatin Hydrogel Nanocomposite Impregnated Co-Doped SnO2 Nanomaterial for the Catalytic Reduction of Environmental Pollutants

In the catalytic reduction of various environment pollutants, cobalt-doped tin oxide, i.e., Co-SnO₂ intercalated gelatin (GL) hydrogel nanocomposite was prepared via direct mixing of Co-SnO₂ doped with GL. Then, it was crosslinked internally using formaldehyde within a viscous solution of gelatin polymer, which led to the formation of GL/Co-SnO₂ hydrogel nanocomposite. GL/Co-SnO₂ hydrogel nanocomposite was fully characterized by using field-emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDX), powder X-ray diffraction (XRD), and attenuated total reflection–Fourier transform infrared spectroscopy (ATR-FTIR). The FESEM images indicate that the Co-SnO₂ composite has a spherical structure on the GL matrix while EDX elucidates the elemental composition of each atom in the crosslinked GL/Co-SnO₂ hydrogel nanocomposite. The GL/Co-SnO₂ nanocomposite was checked for the reduction of various pollutants, including 2-nitro-phenol (2-NP), 2,6-dinitro-phenol (2,6-DNP), 4-nitro-phenol (4-NP), Congo red (CR), and methyl orange (MO) dyes with a strong sodium borohydride (NaBH₄) reducing agent. The GL/Co-SnO₂ nanocomposite synergistically reduced the MO in the presence of the reducing agent with greater reduction rate of 1.036 min⁻¹ compared to other dyes. The reduction condition was optimized by changing various parameters, such as the catalyst amount, dye concentration, and the NaBH₄ amount. Moreover, the GL/Co-SnO₂ nanocomposite catalyst can be easily recovered, is recyclable, and revealed minimal loss of nanomaterials.

Prediction of heterogeneous Fenton process in treatment of melanoidin-containing wastewater using data-based models

Predictive capability of response surface methodology (RSM) and ant colony optimization combined with support vector regression (ACO-SVR) models are applied for determining optimal parameters in the process of heterogeneous Fenton oxidation of melanoidin, a high molecular weight polymer widely produced during fermentation processes generating large quantities of wastewater with intense brown color and extremely high chemical oxygen demand (COD). Prediction of the performance of nano zero-valent iron supported on activated carbon cloth-chitosan (ACC-CH-nZVI) catalysts was carried out using Box-Behnken design (BBD) and analysis of variance to evaluate the interaction of independent variables involved in heterogeneous Fenton reaction. The optimized condition with minimal consumption of H₂O₂ (173 mM) resulted in 77.1% decolorization of melanoidin-contaminated water corresponding to 74.4% COD removal at pH 3 (600 mg/l Fe dosage) for 90 min reaction time. The corresponding weight ratio of H₂O₂ to COD was 0.98, much lower than the stoichiometric value 2.125, indicating the effectiveness of ACC-CH-nZVI as a heterogeneous Fenton-like catalyst. In comparison to previously published experimental results, ACO-SVR model shows higher coefficient of determination (R²; 0.9983) but lower root mean squared error (RMSE) and mean absolute error (MAE) than those of RSM model, indicating relative superiority in prediction capability. Besides, ACO algorithm appears to be a promising tool for improving forecasting accuracy of SVR model. This work demonstrates the applicability of ACO-SVR model in predicting the performance of wastewater treatment using Fenton process with limited number of experiment and exhibits satisfactory prediction results.

Polysaccharides and Metal Nanoparticles for Functional Textiles: A Review

Nanotechnology is a powerful tool for engineering functional materials that has the potential to transform textiles into high-performance, value-added products. In recent years, there has been considerable interest in the development of functional textiles using metal nanoparticles (MNPs). The incorporation of MNPs in textiles allows for the obtention of multifunctional properties, such as ultraviolet (UV) protection, self-cleaning, and electrical conductivity, as well as antimicrobial, antistatic, antiwrinkle, and flame retardant properties, without compromising the inherent characteristics of the textile. Environmental sustainability is also one of the main motivations in development and innovation in the textile industry. Thus, the synthesis of MNPs using ecofriendly sources, such as polysaccharides, is of high importance. The main functions of polysaccharides in these processes are the reduction and stabilization of MNPs, as well as the adhesion of MNPs onto fabrics. This review covers the major research attempts to obtain textiles with different functional properties using polysaccharides and MNPs. The main polysaccharides reported include chitosan, alginate, starch, cyclodextrins, and cellulose, with silver, zinc, copper, and titanium being the most explored MNPs. The potential applications of these functionalized textiles are also reported, and they include healthcare (wound dressing, drug release), protection (antimicrobial activity, UV protection, flame retardant), and environmental remediation (catalysts).

Catalytic Reduction of Environmental Pollutants with Biopolymer Hydrogel Cross-Linked Gelatin Conjugated Tin-Doped Gadolinium Oxide Nanocomposites

In the present study, a biopolymer nanocomposite hydrogel based on gelatin and tin-doped gadolinium oxide (Sn-Gd₂O₃@GH) was prepared for the efficient reduction of water pollutants. The method of Sn-Gd₂O₃@GH preparation consisted of two steps. A Sn-Gd₂O₃ nanomaterial was synthesized by a hydrothermal method and mixed with a hot aqueous solution (T > 60 °C) of gelatin polymer, followed by cross-linking. Due to the presence of abundant functional groups on the skeleton of gelatin, such as carboxylic acid (–COOH) and hydroxyl (–OH), it was easily cross-linked with formaldehyde. The structure, morphology, and composition of Sn-Gd₂O₃@GH were further characterized by the FESEM, XRD, EDX, and FTIR techniques. The FESEM images located the distribution of the Sn-Gd₂O₃ nanomaterial in a GH matrix of 30.06 nm. The XRD patterns confirmed the cubic crystalline structure of Gd₂O₃ in a nanocomposite hydrogel, while EDS elucidated the elemental composition of pure Sn-Gd₂O₃ powder and cross-linked the Sn-Gd₂O₃@GH samples. The synthesized Sn-Gd₂O₃@GH nanocomposite was used for the removal of different azo dyes and nitrophenols (NPs). It exhibited an efficient catalytic reduction of Congo red (CR) with a reaction rate of 9.15 × 10⁻¹ min⁻¹ with a strong NaBH₄-reducing agent. Moreover, the Sn-Gd₂O₃@GH could be easily recovered by discharging the reduced (colourless) dye, and it could be reused for a fresh cycle.

Catalytic reduction of 4-nitrophenol and methylene blue pollutants in water by copper and nickel nanoparticles decorated polymer sponges

In the present study, two catalysts based-on copper and nickel nanoparticles anchored on agarose-coated sponge (Cu-AG-sponge and Ni-AG-sponge) were prepared, respectively. Both catalysts were characterized by analytical techniques of thermogravimetric analysis energy dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM). Spherical Cu and Ni nanoparticles on struts of AG-coated sponge were observed by FESEM and the samples' elemental composition was confirmed by EDX technique. After characterization, the Cu-AG-sponge and Ni-AG-sponge catalysts were tested in 4-nitrophenol (4-NP) and methylene blue dye (MB) reduction in an aqueous medium. The reduction of the 4-NP to 4-aminophenol (4-AP) was achieved up to 95% using the NaBH₄ reductant and Cu-AG-sponge and Ni-AG-sponge catalysts, respectively. Similarly, the rate of reduction of MB was faster for the Cu-AG-sponge as compared to the Ni-AG-sponge which was discussed based-on the catalyst morphology and other factors. The high rate of reactions for the 4-NP and MB reduction suggests that the Cu-AG-sponge and Ni-AG-sponge catalyst possess high catalytic efficiency, low cost and good reusability having the potential to be used in similar other reactions.

Nano zero valent iron encapsulated in graphene oxide for reducing uranium

Nano zero-valent iron (Fe⁰) has been widely used to remove Uranium (U(VI)). In order to enhance the performance of Fe⁰ toward U(VI) removal, the Fe⁰ was assembled into graphene oxide (GO) sheets via 3-aminopropyl triethoxysilane (APTES) as Fe⁰/APTES-GO composites. The Fe⁰/APTES-GO composites were triumphantly prepared, characterized and analyzed by means of Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM) together with Energy Dispersive Spectrometer (EDS), X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR) and X-ray Photoelectron Spectroscopy (XPS). SEM and TEM-EDS results manifested that Fe⁰ particles were encapsulated into rolled-up GO, which greatly improved the stability of Fe⁰. Batch experiment showed that only a small amount of Fe²⁺ was leached in the first two leaching cycles of Fe⁰/APTES-GO composites. The removal capacity of Fe⁰/APTES-GO composites was up to 1357.99 mg/g at pH = 4.1 and T = 50 °C, which was mainly attributed to the reducing activity of Fe⁰ and an abundance of functional groups (i.e., -COOH, C-OH and -OH) on the Fe⁰/APTES-GO composites. The electrostatic potential (ESP) from the calculation also supported that U(VI) tended to be reduced at the back side of the GO-Fe⁰ cluster.

A review of recent and emerging antimicrobial nanomaterials in wastewater treatment applications

In this paper, we present a critical review on antimicrobial nanomaterials with demonstrated potential for application as a disinfection technology in wastewater treatment. Studies involving fabrication and testing of antimicrobial nanomaterials for wastewater treatment were gathered, critically reviewed, and analyzed. Our review shows that there are only a few eligible candidate nanoparticles (NPs) (metal and metal oxide) that can adequately serve as an antimicrobial agent. Nanosilver (nAg) was the most studied and moderately understood metal NPs with proven antimicrobial activity followed by ZnO (among antimicrobial metal oxide NPs) which outperformed titania (in the absence of light) in efficacy due to its better solubility in aqueous condition. The direction of future work was found to be in the development of antimicrobial nanocomposites, since they provide more stability for antimicrobial metal and metal oxides NPs in water, thereby increasing their activity. This review will serve as an updated survey, yet touching also the fundamentals of the antimicrobial activity, with vital information for researchers planning to embark on the development of superior antimicrobial nanomaterials for wastewater treatment applications.

Comparative efficacy of biogenic zinc oxide nanoparticles synthesized by Pseudochrobactrum sp. C5 and chemically synthesized zinc oxide nanoparticles for catalytic degradation of dyes and wastewater treatment

Discharge of untreated textile wastewaters loaded with dyes is not only contaminating the soil and water resources but also posing a threat to the health and socioeconomic life of the people. Hence, there is a need to devise the strategies for effective treatment of such wastewaters. The present study reports the catalytic potential of biogenic ZnO nanoparticles (ZnO NPs) synthesized by using a bacterial strain Pseudochrobactrum sp. C5 for degradation of dyes and wastewater treatment. The catalytic potential of the biogenic ZnO NPs for degradation of dyes and wastewater treatment was also compared with that of the chemically synthesized ones. The characterization of the biogenic ZnO NPs through FT-IR, XRD, and field emission scanning electron microscopy (FESEM) indicated that these are granular agglomerated particles having a size range of 90-110 nm and zeta potential of -27.41 mV. These catalytic NPs had resulted into almost complete (> 90%) decolorization of various dyes including the methanol blue and reactive black 5. These NPs also resulted into a significant reduction in COD, TDS, EC, pH, and color of two real wastewaters spiked with reactive black 5 and reactive red 120. The findings of this study suggest that the biosynthesized ZnO NPs might serve as a potential green solution for treatment of dye-loaded textile wastewaters.

Eggshell membranes coated chitosan decorated with metal nanoparticles for the catalytic reduction of organic contaminates

This study focusses on the effect of chitosan coating with eggshell membranes for the reduction of different organic pollutants. Chickens eggs were collected from the local market and utilized to extract the enrich eggshell membranes (ESM). The chicken eggshell membranes are abundant waste material which is inexpensive and illustrates remarkable physiognomies for many possible applications. Fresh fibers/strips coated by chitosan (CS) were prepared by mixing the eggshell membranes with CS solution (2 wt%/v) in different proportions i.e., 10 %, 30 %, 50 %, 60 %, 70 %, 80 %, and 90 %. These strips were then templated with copper and iron metal nanoparticles by putting them in their metal ions aqueous solution to adsorb the metals ions and were then reduced to zero-valent metal nanoparticles (MNPS) by using NaBH₄ aqueous solution. These prepared materials (MNPS@ESM-CS) were characterized by using XRD, XPS, FE-SEM, and EDS to confirm the successful preparation of MNPs over the surface of ESM coated with CS. Afterwards, these prepared materials were investigated as a catalyst for the reduction of different organic pollutants, such as 4-nitroaniline (4-NA), 4-nitrophenol (4-NP) and methylene blue (MB) dye. The catalytic efficiency of ESM was enhanced 5.7-fold by adding only 20 % CS solution. It was observed that Cu@ESM-CS-80 % took 7 min for reduction of 4-NA, 6 min for 4-NP, and 7 min for MB dye. The reusability of the catalytic strip was also investigated for four cycles and found efficient and can be easily recovered by simply pulling it from the reaction mixture.

Nano zero-valent iron on activated carbon cloth support as Fenton-like catalyst for efficient color and COD removal from melanoidin wastewater

To reduce undesired iron leaching in Fenton reaction and to realize reusability of catalyst, chitosan-coated activated carbon cloth support loaded with nano zero-valent iron (ACC-CH-nZVI) was applied as a heterogeneous Fenton catalyst to treat melanoidin wastewater. Chitosan coating on ACC by chemical crosslinking results in 6% chitosan on ACC subsequently loading 3.5% iron. At optimum conditions, ACC-CH-nZVI leads to 88.4% and 76.2% of color and chemical oxygen demand (COD) removal, respectively, upon treating synthetic melanoidin wastewater of 8000 mg/l COD. The corresponding weight ratio of consumed H₂O₂ to COD is 1.02, far below the stoichiometric ratio 2.125, indicating the economic value of this catalyst. Reusability of ACC-CH-nZVI is demonstrated for five cycles of treatment with minimal iron leaching (<2%). The high removal efficiency and very low levels of iron leaching suggests that ACC-CH-nZVI is a highly efficient and cost-effective catalyst for Fenton-like oxidation of non-biodegradable organic wastes in water.

Catalytic potential of cobalt oxide and agar nanocomposite hydrogel for the chemical reduction of organic pollutants

In this study, cobalt oxide nanoparticles (Co₃O₄ NPs) were synthesized by precipitation method from cobalt sulphate solution with basic pH, followed by calcination. The ex-situ synthesized Co₃O₄ NPs were mixed with hot agar (AG) aqueous solution. The preparation of AG- Co₃O₄ nanocomposite hydrogel was carried out by self-association method promoted by thermal denaturation. The quenching of hot suspension from 80 °C to room temperature resulted in the formation of AG-Co₃O₄ nanocomposite hydrogel. The as-synthesized AG-Co₃O₄ was characterized by FTIR, XRD and SEM techniques. In order to test the catalytic activity, AG-Co₃O₄ was used as a heterogeneous catalyst for the reduction of methylene blue (MB), congo red (CR) and 4-nitrophenol (4-NP). The excellent performance of the AG-Co₃O₄ was shown by the reaction rate constant (k_app) values of 0.3623, 0.2114 and 0.2893 for MB, 4-NP and CR, respectively. All these results were obtained with R² above 94 and utilization of an AG-Co₃O₄ catalyst. Furthermore, the catalytic reduction was studied with varying dye concentration and catalyst dose. This study showed that AG-Co₃O₄ catalyst has high potential for remediation of environmental pollutants in wastewaters.

Switching from Conventional to Nano-natural Phytochemicals to Prevent and Treat Cancers: Special Emphasis on Resveratrol

BACKGROUND

Natural phytochemicals and their derivatives have been used in medicine since prehistoric times. Natural phytochemicals have potential uses against various disorders, including cancers. However, due to low bioavailability, their success in clinical trials has not been reproduced. Nanotechnology has played a vital role in providing new directions for diagnosis, prevention, and treatment of different disorders, and of cancer in particular. Nanotechnology has demonstrated the capability to deliver conventional natural products with poor solubility or a short half-life to target specific sites in the body and regulate the release of drugs. Among the natural products, the phytoalexin resveratrol has demonstrated therapeutic effects, including antioxidant, antiinflammatory, and anti-proliferative effects, as well as the potential to inhibit the initiation and promotion of cancer. However, low water solubility and extensive first-pass metabolism lead to poor bioavailability of resveratrol, hindering its potential. Conventional dosage forms of resveratrol, such as tablets, capsules, dry powder, and injections, have met with limited success. Nanoformulations are now being investigated to improve the pharmacokinetic characteristics, as well as to enhance the bioavailability and targetability of resveratrol.

OBJECTIVES

This review details the therapeutic effectiveness, mode of action, and pharmacokinetic limitations of resveratrol, as well as discusses the successes and challenges of resveratrol nanoformulations. Modern nanotechnology techniques to enhance the encapsulation of resveratrol within nanoparticles and thereby enhance its therapeutic effects are emphasized.

CONCLUSION

To date, no resveratrol-based nanosystems are in clinical use, and this review would provide a new direction for further investigations on innovative nanodevices that could consolidate the anticancer potential of resveratrol.

Pollution, Toxicity and Carcinogenicity of Organic Dyes and their Catalytic Bio-Remediation

Water pollution due to waste effluents of the textile industry is seriously causing various health problems in humans. Water pollution with pathogenic bacteria, especially Escherichia coli (E. coli) and other microbes is due to the mixing of fecal material with drinking water, industrial and domestic sewage, pasture and agricultural runoff. Among the chemical pollutants, organic dyes due to toxic nature, are one of the major contaminants of industrial wastewater. Adequate sanitation services and drinking quality water would eliminate 200 million cases of diarrhea, which results in 2.1 million less deaths caused by diarrheal disease due to E. coli each year. Nanotechnology is an excellent platform as compared to conventional treatment methods of water treatment and remediation from microorganisms and organic dyes. In the current study, toxicity and carcinogenicity of the organic dyes have been studied as well as the remediation/inactivation of dyes and microorganism has been discussed. Remediation by biological, physical and chemical methods has been reviewed critically. A physical process like adsorption is cost-effective, but can't degrade dyes. Biological methods were considered to be ecofriendly and cost-effective. Microbiological degradation of dyes is cost-effective, eco-friendly and alternative to the chemical reduction. Besides, certain enzymes especially horseradish peroxidase are used as versatile catalysts in a number of industrial processes. Moreover, this document has been prepared by gathering recent research works related to the dyes and microbial pollution elimination from water sources by using heterogeneous photocatalysts, metal nanoparticles catalysts, metal oxides and enzymes.

Gamma radiation-assisted in situ synthesis of palladium nanoparticles supported on ethylenediamine-functionalized polypropylene fabric as an efficient catalyst for reduction of 4-nitrophenol

Immobilization of Pd nanometals on a functionalized non-woven polypropylene fabric offers heterogenous catalytic activity in many chemical transformations and convenient separation from the reaction mixture.

Lignocellulosic biomass supported metal nanoparticles for the catalytic reduction of organic pollutants

Lignocellulosic biomass waste is a cheap, eco-friendly, and sustainable raw material for a wide array of applications. In the present study, an easy, fast, and economically feasible route has been proposed for the preparation of different zero-valent metal nanoparticles (ZV-MNPs) based on Cu, Co, Ag, and Ni NPs using empty fruit bunch (EFB) biomass residue as support material. The catalytic efficiency of ZV-MNPs/EFB catalyst was investigated against five model pollutants, such as methyl orange (MO), congo red (CR), methylene blue (MB), acridine orange (AO), and 4-nitrophenol (4-NP) using NaBH₄ as a source of hydrogen and electron. Comparative study revealed that among as-prepared ZV-MNPs/EFB catalysts, Cu-NPs immobilized onto EFB (Cu/EFB) exhibited maximum catalytic efficiency towards pollutant abasement. Degradation reactions were highly efficient, and were completed within a short time (4 min) in case of MO, CR, and MB, whilst AO and 4-NP were reduced in less than 15 min. Kinetic investigation revealed that the degradation rate of model pollutants accorded with pseudo-first order model. Furthermore, supported catalysts were easily recovered after the completion of experiment by simply pulling the catalyst from reaction system. Recyclability tests performed on Cu/EFB revealed that more than 97% of the reduction was achieved in case of MO dye for four successive cycles of reuse. The as-prepared heterostructure showed multifunctional properties, such as enhanced uptake of contaminants, high catalytic efficiency, and easy recovery, hence, offers great prospects in wastewater purification.

Comparative Synthesis and Characterization of Bio-Cellulose from Local Waste and Cheap Resources

Background:

Bacterial cellulose (BC) has been extensively utilized in a wide range of applications specifically in the biomedical field thanks to its excellent physico-chemical and biological features. The major limitation restricting its application in certain areas is its high production cost. Its widespread applications demand exploration of alternative production media compared to the existing expensive ones. Herein, an effort has been made to utilize waste and cheaply available local resources including; waste (expired) orange juice (WOJ), sugarcane juice (SC) and coconut water (CW) as alternative media for BC production in comparison to the synthetic media (control).

Methods:

Waste and cheap resources were collected from the local market, screened filtered and optimized for the development of BC culture media. BC production from all media was observed under static cultivation for 10 days. The results indicated 2.75, 2.56, 3.32 and 1.68 g/L BC production that corresponded to 27.5%, 21.7 %, 20.1 % and 31.6 % sugar to BC conversion from control, WOJ, SC and CW media, respectively. Morphology and crystalline features of produced BC samples were observed through FE-SEM and XRD analysis. It was noteworthy that BC produced from all alternative sources indicated high water holding capabilities (WHC) and water retention time (WRT) that augment their applicability in drug delivery and wound healing applications.

Conclusion:

The BC production from cheap resources and its high physical, mechanical and biological properties can be of high interest for scaling up and commercialization of BC production processes. Furthermore, its liquidabsorbing capabilities and retention time can help in drug carrying and medical application.

Biocompatible Polymers and their Potential Biomedical Applications: A Review

Background:

Biocompatible polymers are gaining great interest in the field of biomedical applications. The term biocompatibility refers to the suitability of a polymer to body and body fluids exposure. Biocompatible polymers are both synthetic (man-made) and natural and aid in the close vicinity of a living system or work in intimacy with living cells. These are used to gauge, treat, boost, or substitute any tissue, organ or function of the body. A biocompatible polymer improves body functions without altering its normal functioning and triggering allergies or other side effects. It encompasses advances in tissue culture, tissue scaffolds, implantation, artificial grafts, wound fabrication, controlled drug delivery, bone filler material, etc.

Objectives:

This review provides an insight into the remarkable contribution made by some well-known biopolymers such as polylactic-co-glycolic acid, poly(ε-caprolactone) (PCL), polyLactic Acid, poly(3- hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), Chitosan and Cellulose in the therapeutic measure for many biomedical applications.

Methods: :

Various techniques and methods have made biopolymers more significant in the biomedical fields such as augmentation (replaced petroleum based polymers), film processing, injection modeling, blow molding techniques, controlled / implantable drug delivery devices, biological grafting, nano technology, tissue engineering etc.

Results:

The fore mentioned techniques and other advanced techniques have resulted in improved biocompatibility, nontoxicity, renewability, mild processing conditions, health condition, reduced immunological reactions and minimized side effects that would occur if synthetic polymers are used in a host cell.

Conclusion:

Biopolymers have brought effective and attainable targets in pharmaceutics and therapeutics. There are huge numbers of biopolymers reported in the literature that has been used effectively and extensively.

Core-Shell Molecularly Imprinted Polymer Nanocomposites for Biomedical and Environmental Applications

Core-shell polymers represent a class of composite particles comprising of minimum two dissimilar constituents, one at the center known as a core which is occupied by the other called shell. Core-shell molecularly imprinting polymers (CSMIPs) are composites prepared via printing a template molecule (analyte) in the coreshell assembly followed by their elimination to provide the everlasting cavities specific to the template molecules. Various other types of CSMIPs with a partial shell, hollow-core and empty-shell are also prepared. Numerous methods have been reported for synthesizing the CSMIPs. CSMIPs composites could develop the ability to identify template molecules, increase the relative adsorption selectivity and offer higher adsorption capacity. Keen features are measured that permits these polymers to be utilized in numerous applications. It has been developed as a modern technique with the probability for an extensive range of uses in selective adsorption, biomedical fields, food processing, environmental applications, in utilizing the plant's extracts for further applications, and sensors. This review covers the approaches of developing the CSMIPs synthetic schemes, and their application with special emphasis on uses in the biomedical field, food care subjects, plant extracts analysis and in environmental studies.

Preparation and Characterization of Agar Based Magnetic Nanocomposite for Potential Biomedical Applications

PURPOSE

The purpose of the present study was to make a biocompatible agar based composite material via incorporation of appropriate additives within the agar matrix for potential applications in drug delivery and biomedical fields.

METHODOLOGY

Agar based composites were prepared by the incorporation of magnetic iron oxide nano particles, graphite and sodium aluminum as additives in different proportions within the agar matrix by a simple thermophysico- mechanical method. The as prepared agar based composites were then characterized by different techniques i.e. FTIR, SEM, TGA, XRD and EDX analyses. The FTIR peaks confirmed the presence of each component in the agar composite. SEM images showed the uniform distribution of each component in the agar composite. TGA study showed the thermal stability range of different composite sheets. XRD pattern revealed the crystallinity and EDX analysis confirmed the elemental composition of the prepared composites. The prepared agar based composites were evaluated for antimicrobial activities against three pathogenic bacterial strains Escherichia coli, Staphylococcus aureus and Klebsiella pneumonia and the result indicated efficient antimicrobial activities for all composites.

CONCLUSION

From the overall study, it was concluded that due to the non-toxic nature, thermal stability and excellent antibacterial properties, the prepared agar based composites can receive potential biomedical applications.

Copper(II) oxide nanoparticles coated cellulose sponge-an effective heterogeneous catalyst for the reduction of toxic organic dyes

Discharge of unprocessed coloured waste water from industries gives rise to water contamination. In the current work, we propose the application of CuO nanoparticles supported on cellulose kitchen wipe sponge as a heterogeneous catalyst for the reductive decolourization of various toxic cationic and anionic dye molecules. The catalytic activity of the CuO nanoparticles under normal light for reduction has been examined in which sunlight irradiation is not necessitated. The CuO nanoparticles were synthesized by a simple wet chemical method and characterized using High Resolution Transmission Electron Microscope (HRTEM), SEM, EDX, XRD, XPS and TGA analyses. In the presence of CuO@CS catalyst and sodium borohydride, decolourization reaction of dyes such as acid red, acid green, methylene blue, rhodamine B and solochrome black-T was carried out. The catalytic reduction behaves as a pseudo-first-order reaction and is found to be superior in comparison with other reported catalysts in terms of reaction velocity. The reduction reaction can be further accelerated by increasing the reaction temperature. The developed catalyst drives the reduction faster on exposing the reaction mixture to sunlight confirming the usage of the catalyst at normal light and sunlight conditions. The catalyst retains 100% efficiency even after 5 cycles and remains suitable even for further use. Thus, a low-cost heterogeneous catalyst has been successfully developed and employed to decolourize various dye molecules in short duration with good recyclability and therefore can be used as the potential candidate in environmental remediation.

Chitosan Nanocomposite Coatings for Food, Paints, and Water Treatment Applications

Worldwide, millions of tons of crustaceans are produced every year and consumed as protein-rich seafood. However, the shells of the crustaceans and other non-edible parts constituting about half of the body mass are usually discarded as waste. These discarded crustacean shells are a prominent source of polysaccharide (chitin) and protein. Chitosan is a de-acetylated form of chitin obtained from the crustacean waste that has attracted attention for applications in food, biomedical, and paint industries due to its characteristic properties, like solubility in weak acids, film-forming ability, pH-sensitivity, biodegradability, and biocompatibility. We present an overview of the application of chitosan in composite coatings for applications in food, paint, and water treatment. In the context of food industries, the main focus is on fabrication and application of chitosan-based composite films and coatings for prolonging the post-harvest life of fruits and vegetables, whereas anti-corrosion and self-healing properties are the main properties considered for antifouling applications in paints in this review.